سنتز پلیمرهای شاخه‌دار و پراکنش نانوذرات سیلیکا و اثر برهم‌کنش آن‌ها بر شکل‌شناسی سیمان آبدار شده

نوع مقاله : پژوهشی

نویسندگان

تهران، پژوهشگاه پلیمر و پتروشیمی ایران، پژوهشکده مهندسی، گروه مهندسی پلیمریزاسیون، صندوق پستی: 112- 14975

چکیده

انواع پلیمرهای شاخه‌دار از واکنش پلیمرشدن درجای رادیکالی آزاد مونومرهای آکریلیک اسید (AA)، مالئیک انیدرید (MA) و پلی‌اتیلن گلیکول متیل‌اتر متاکریلات با وزن مولکولی   950g/mol (PEGMA) با درصدهای مختلف از نانوذرات سیلیکا سنتز شدند. شناسایی ساختاری این ترکیبات با روش‌های طیف‌سنجی زیرقرمز تبدیل فوریه (FTIR)، رزونانس مغناطیسی هسته هیدروژن (1HNMR) و سوانگاری ژل تراوایی (GPC) انجام شد. نتایج بررسی برهم‌کنش میان پلیمرهای شاخه‌دار با نانوذرات با گرماوزن‌سنجی (TGA‌) نشان داد، در شرایط اسیدی پیوندهای هیدروژنی میان عاملیت‌های موجود در زنجیر پلیمری با سطح نانوذرات بسیار قوی‌تر از شرایط خنثی است. همچنین، نوع برهم‌کنش میان عاملیت‌های موجود در زنجیر پلیمری با گروه‌های هیدروکسی موجود در سطح نانوذرات در شرایط اسیدی و خنثی متفاوت است. بررسی پراکنش نانوذرات سیلیکا در مجاورت پلیمرهای شاخه‌دار با استفاده از روش‌های پراکندگی نور دینامیکی (DLS) و میکروسکوپی الکترونی پویشی (SEM) انجام شد. نتایج نشان داد، در شرایط اسیدی اندازه ذرات بسیار بزرگ بوده و پراکنش به‌خوبی انجام نشد. در شرایط خنثی و پس از صوت‌دهی، نیز پراکنش نانوذرات به‌خوبی انجام شد. همچنین، با افزایش درصد وزنی نانوذرات از %7/4 به %23 وزنی، مقدار پراکنش نانوذرات کمتر ‌شد. افزون براین، نتایج SEM مربوط به سطح مقطع سیمان نشان داد، نانوذرات پراکنده شده به‌خوبی درون سیمان توزیع می‌شوند و پلیمرهای شاخه‌دار روی شکل‌شناسی ساختار بلور‌های ایجاد شده در سیمان اثر شایان توجهی دارند. نتایج پراش پرتو X با انرژی پاشنده (EDAX) نشان داد، پلیمرهای شاخه‌دار و نانوذرات به‌خوبی درون سیمان پخش شدند.

کلیدواژه‌ها


عنوان مقاله [English]

Synthesis of Branched Polymers and Dispersion of Nanosilica and the Effect of Their Interaction on Hydrated Cement Morphology

نویسندگان [English]

  • Mohammad Reza Rostami Darounkola
  • Mehrdad Fallah
Department of Polymerization Engineering, Faculty of Polymerization, Iran Polymer and Petrochemical Institute, P.O. Box: 14975-112, Tehran, Iran
چکیده [English]

Hypothesis: Dispersion and stabilization of silica nanoparticles are novel approach in the synthesis of hybrid materials in interacting with cement particles. Branched polymers are able to enhance the dispersion and stability of these nanoparticles. Dispersed nanosilica and branched polymers have direct effects on the microstructure of cement. These materials have wide applications in concrete technology.
Methods: Various branched polymers were synthesized through in situ radical polymerization of acrylic acid, maleic anhydride and polyethylene glycol methyl ether methacrylate (Mn=950 g/mol) in presence of nanosilica with different contents.
Findings: The molecular structures of the synthesized branched polymers were characterized by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC) methods. Thermogravimetric analysis was used to identify the nature of interactions between the branched polymers and nanoparticles. The dispersion state of nanosilica particles within branched polymer solution was studied by dynamic light scattering (DLS) and scanning electron microscopy (SEM) analysis. The results showed a low dispersion in acidic conditions due to agglomeration of nanosilica in the cement. Furthermore, after 30 min sonication, in a neutralized condition, the nanoparticles were dispersed well. In addition, the dispersibility of nanosilica dropped with increases in nanosilica loading. The SEM images showed good dispersion of nanoparticles in the cement medium. It was also demonstrated that the branched polymer had a great influence on the morphology of crystal structure formation in the hydrated cement. The SEM images revealed the best distribution of nanoparticles with 4.7 weight percent nanosilica in the presence of neutralized branching polymers under sonication. From the EDAX results it was also found that the nanosilica particles and branched polymers were dispersed well in the cement medium.

کلیدواژه‌ها [English]

  • branched polymer
  • dispersion
  • nanoparticles
  • silica fume
  • micronized cement particles
  1. Lin S.H., Lai S.M., Lin C.M., Chou C.W., and Lee C.H., Preparation and Characterization of Polystyrene Sulfonic Acid-Co-Maleic Acid Copolymer Modified Silica Nanoparticles, J. Polym. Res., 23, 44, 2016.
  2. Jing X., Gong W., Feng Zh., Meng X., and Zheng B., Influence of Comb-like Copolymer Dispersants with Different Molecular Structures on the Performance of CaCO3 Suspension in Organic System, J. Disper. Sci. Technol., 38, 1311-1318, 2017.
  3. Liu J., Ran Q., Miao Ch., and Zhou D., Synthesis and Characterization of Comb-Like Copolymer Dispersant with Methoxy Poly(ethylene oxide) Side Chains, Polym-Plast Technol. Eng., 50, 59-66, 2011.
  4. Jin H., Chen Q., Wu Sh., and Shen J., Effect of Length of Branched-chain of PAA-g-MPEO on Dispersion of CaCO3 Aqueous Suspensions, Polym. Bull, 68, 597-605, 2012.
  5. Whitby C.P., Scales P.J., Grieser F., Healy T.W., Kirby G., Lewis J.A., and Zukoski C.F., PAA/PEO Comb Polymer Effects on Rheological Properties and Inter Particle Forces in Aqueous Silica Suspensions, J. Colloid. Interface Sci., 262, 274-281, 2003.
  6. Akhlaghi O., Akbulut O., and Menceloglu Y.Z., Extensional Rheology and Stability Behavior of Alumina Suspensions in the Presence of AMPS-Modified Polycarboxylate Ether-based Copolymers, Colloid. Polym. Sci., 293, 2867-2876, 2015.
  7. Erzengin S.G., Kaya K., Özkorucuklu S.P., Özdemir V., and Yıldırım G., The Properties of Cement Systems Superplasticized with Methacrylic Ester-Based Polycarboxylates, Construct. Build. Mater., 166, 96-109, 2018.
  8. Kong F.R., Pan L.Sh., Wang Ch.M., Zhang D.L., and Xu N., Effects of Polycarboxylate Superplasticizers with Different Molecular Structure on the Hydration Behavior of Cement Paste,  Construct. Build. Mater., 105, 545-553, 2016.
  9. Wang A., Qiao M., Xu J., Pan Y., Ran Q., Wu Sh., and Chen Q., POEGMA-b-PAA Comb-like Polymer Dispersant for Al2O3 Suspensions, J. Appl. Polym. Sci., 133, 43352-43357, 2016.
  10. Cho H.Y. and Sun J.M., Effects of the Synthetic Conditions of Poly{carboxylate-g-(ethylene glycol) methyl ether} on the Dispensability in Cement Paste, Cement and Concrete Res., 35, 891-899, 2005.
  11. Winnefeld F., Becker S., Pakusch J., and  Götz T., Effects of the Molecular Architecture of Comb-shaped Superplasticizers on Their Performance in Cementitious Systems., Cement Concrete Compos., 29, 251-262, 2007.
  12. Plank J., Pöllmann K., Zouaoui N., Andres P.R., and Schaefer C., Synthesis and Performance of Methacrylic Ester Based Polycarboxylate Superplasticizers Possessing Hydroxy Terminated Poly(ethylene glycol) Side Chains, Cement Concrete Res., 38, 1210-1216, 2008.
  13. Jin H., Chen Q., Wu Sh., and Shen J., Effect of Length of Branched-Chain of PAA-g-MPEO on Dispersion of CaCO3 Aqueous Suspensions, Polym. Bull., 68, 597-605, 2012.
  14. Zhu J., Li Y., Zhang G., Wang R., and Qu Q., Impact of the length of PEO Side Chain on the Properties of Polycarboxylate Copolymers in Coal-water Suspensions, Colloid Polym. Sci., 293, 1093-1100, 2015.
  15. Imani M., Sharifi Sh., Mirzadeh H., and Ziaee F., Monitoring of Polyethylene Glycoldiacrylate-based Hydrogel Formation by Real Time NMR Spectroscopy, Iran. Polym. J., 1, 13-20, 2007.
  16. Miladinovic Z.R., Micic M., and Suljovrujic E., Temperature/pH Dual Responsive OPGMA Based Copolymeric Hydrogels Prepared by Gamma Radiation: An Optimisation Study, J. Polym. Res., 23, 77, 2016.
  17. Kim B. and Peppas N.A., Analysis of Molecular Interactions in Poly(methacrylic acid-g-ethylene glycol) Hydrogels, Polymer, 44, 3701-3707, 2003.
  18. Rostami Daronkola M.R., Synthesis and Characterization of Different Quaterpolymers as Superplasticizer and Their Effectiveness on Micronized Cement Particles, Iran. Polym. J. Sci. Technol.  (Persian), 30, 221-233, 2017.  
  19. Yamada K., Takahashi T., Henahara S., and Matsuhira M., Effects of the Chemical Structure on the Properties of Polycarboxylate Type Superplasticizer, Cement Concrete Res., 30, 197-207, 2000.
  20. Plank J., Zhimin D., Keller H., Hössle F., and Seid W., Fundamental Mechanisms for Polycarboxylate Intercalation into C3A Hydrate Phases and the Role of Sulfate Present in Cement, Cement Concrete Res., 40, 45-57, 2010.
  21. Li Y.,Yang Ch., Zhang Y., Zheng J., Guo H., and Lu M., Study on Dispersion, Adsorption and Flow Retaining Behaviors of Cement Mortars with TPEG-type Polyether Kind Polycarboxylate Superplasticizers, Construct. Build. Mater., 64, 324-332, 2014.
  22. Rostami Darounkola M.R., Novel Branched Polymers and Their Structural Effects on Intercalation into Na-MMT and Silica Fume Suspensions, Polym. Bull., 75, 4055-4072, 2018.
  23. Jafari V., Allahverdi A., and Vafaei M., Ultrasound-assisted Synthesis of Colloidal Nanosilica from Silica Fume: Effect of Sonication Time on the Properties of Product, Adv. Powder Technol., 25, 1571-1577, 2014.
  24. SadeghHassani S., Rashidi A., Adinehnia M., and Montakhaba N., Facile and Economic Method for Preparation of Nanocolloidal Silica with controlled Size and Stability, Int. J. Nano Dimens., 5, 177-185, 2014.
  25. Zhou L., Zhang, H., Zhang H., and Zhang Z., Homogeneous Nanoparticle Dispersion Prepared with Impurity-free Dispersant by the Ball Mill Technique, Particuology,  11, 441-447, 2013.
  26. Biricik H. and Sarier N., Comparative Study of the Characteristics of Nanosilica, Silica Fume and Fly Ash Incorporated Cement Mortars, Mater. Res., 17, 570-582, 2014.
  27. Mohammadi Atashgah K., Hashempour, H., and Karbalaei Rezaei M., An Investigation into the Role of Nano-Silica in Improving Strength of Lightweight Concrete, Eur. Online J. Natural Soc. Sci., 3, 1058-1067, 2014.
  28. Singh L.P., Agarwal S.K., Bhattacharyya S.K., Sharma U., and Ahalawat S., Preparation of Silica Nanoparticles and Its Beneficial Role in Cementitious Materials, Nanomater. Nanotechnol., 1, 44-51, 2011.
  29. Li L.G., Huang Z.H., Zhu J., Kwan A.K.H., and Chen H.Y., Synergistic Effects of Micro-Silica and Nano-silica on Strength and Microstructure of Mortar, Construct. Build. Mater., 140, 229-238, 2017.
  30. Meier M.R., Napharatsamee T., and Plank J., Dispersing Performance of Superplasticizers Admixed to Aged Cement, Construct. Build. Mater., 139, 232-240, 2017.
  31. Land G. and Stephan D., Controlling Cement Hydration with Nanoparticles, Cement Concrete Compos., 57, 64-67, 2015.
  32. Gaël B., Christelle T., Gilles E., Sandrine G., and Tristan S.F., Determination of the Proportion of Anhydrous Cement Using SEM Image Analysis, Construct. Build. Mater., 126, 157-164, 2016.